Table 1.

Maternal hormone concentration and peak concentration time in each trimester and in non-pregnant women.

Hormone	Peak time				Daytime/Nighttime concentrations
	NP	1T	2T	3T	NP	1T	2T	3T
Melatonin	Follicular and Luteal: 01:00 (18)	00:00–4:00 (9–13 weeks) (19)	00:00–04:00 (24–37 weeks) (19)		41.7 pmol/L (11:00) (19)/ ~200 pmol/L (03:00) (20)	29.97 pmol/L (11:00) (19)/ 245.1 pmol/L (04 :00) (19)	39.1 pmol/L (11:00) (19)/ 663.5 pmol/L (04 :00) (19)	76.5 pmol/L (11:00) (19)/ 663.5 pmol/L (04 :00) (19)
Dopamine	08:00 (Men) (21)	nd	nd	nd	nd	nd	nd	nd
Cortisol	07:00 (22)	07:00–09:00 (23)	07:00–09:00 (23)	07:00–09:00 (23) 08:00 (30–39 weeks) (24)	292 nmol/L (07:00) (22)/ 70 nmol/L (01:00) (22)	149 ng/mL (08:00) (23)/ nd	352 ng/mL (08:00) (23)/ nd	~400 ng/mL (08:00) (23, 24)/ ~200 ng/mL (00:30) (24)
Progesterone	Follicular:11:00 (18) Luteal:14:00 (18)	24:00–01:00 (6–10 weeks) (25)	nd	nd	nd	40.2 ng/mL (24:00) (25)/26.4 ng/mL (08:00) (25)	nd	nd
Estrogen	Follicular: 01:00 (18) Luteal: 02:00 (18) (estradiol)	nd	nd	01:30–03:30 (30–31 weeks) (24) 22:30–00:30 (34–35 weeks) (24) (Estriol)	nd	nd	nd	~6.0 ng/mL 01:30–03:30 (30–31 weeks) 22:30–00:30 (34–35 weeks) (24)/5 ng/mL 09:00–10:30 (30–31 weeks) 4.7 ng/mL 10:00–11:30 (34–35 weeks) (24)

^##Relevant reference for peak time and concentration in parentheses.

NP, Non-pregnant; 1T, First Trimester; 2T, Second Trimester; 3T, Third Trimester.

Nd, No data.

Peak time: Time of day of sample collection and (gestational age of measurements).

Day/Night: concentrations and (time of day of sample collection).